What are some alternatives?
Miraheze - Miraheze is a wiki farm (hosts wikis) for free and with no ads, it also provides custom domains...
Wikipedia - Wikipedia is a free online encyclopedia, created and edited by volunteers around the world and hosted by the Wikimedia Foundation.
TiddlyWiki - TiddlyWiki — a non-linear personal web notebook
Torchpad - Wiki farm with markdown based wikis.
LibreOffice - Base - Base, database, database frontend, LibreOffice, ODF, Open Standards, SQL, ODBC
Infogalactic - The planetary knowledge core